There is a popular perception of constant danger at borders. Unfortunately, such dangers do exist, and they are largely a consequence of the immigration controls and the War on Drugs (see Chapter 12). The opportunity to conduct a lucrative arbitrage is a powerful motivator to break the law. Human traffickers and drug cartel hitmen are largely the creatures of government prohibition.
If border restrictions were to be lifted, dangers currently associated with international borders would largely evaporate as well. The current restrictions focus a great deal on smuggling of contraband. Without such distractions, the line between hostile invaders and peaceful travelers would be much easier to discern. Libertarians generally believe that there is a real need for security services both locally and regionally.
Many liberty-minded writers have discussed how markets might produce security services (some are mentioned in the "Additional Resources" list at the end of this chapter). As a practical question, there can be no doubt that private firms are capable of going to war. Global mercenary operations in the years following the war in Vietnam demonstrated that private firms are more efficient at ending short-term conflicts and stabilizing an area of operations than government forces. Many thousands of military contractors were used in American operations during the Iraq and Afghanistan wars. Private contractors made up as much as one-fifth of the total occupation force in Iraq.
This question is from Faith Seeking Freedom: Updated & Expanded, available in paperback, PDF, and Kindle.